docs README: change download links ffmpeg

Signed-off-by: Conrad Zelck <git@simpel.cc>

README.md

@@ -22,4 +22,4 @@ So you can use the app as an audio extractor or audio converter too.
 
 As windows FFmpeg build is licensed under GPL and therefor incompatible with MIT license I can't offer a compiled release.  
 FFmpeg source can be found here: https://github.com/FFmpeg/FFmpeg  
-You can download FFmpeg build under: https://ffmpeg.zeranoe.com/build
+You can download FFmpeg build under: https://www.gyan.dev/ffmpeg/builds or https://github.com/BtbN/FFmpeg-Builds/releases